Hi ASC,
Are you accessing your email on more than one device?
When I first starting syncing emails to multiple devices, I notices emails would 'disappear' too, then realized, it was because I had deleted them on another device, -
but had forgot to set that device's email settings to
store mail on Server - as a result this is what was going on:
- Received an email on Desktop and read it
- Later in day I read same email on a Smart Phone and then deleted it on phone
- But as I had not gone to settings on phone & checked to keep mail on server, the server deleted the email too.
- Thus when I next opened Mail app on Desktop and it synced to the Server, it refreshed the inbox which now no longer had that email, and thus removed it from Desktop
That may be what is going on in your case.